8 This we have said in the case where the things done are similar. In the case where they are diverse, we find a man by charity made fierce; and by iniquity made winningly gentle. A father beats a boy, and a boy-stealer caresses. If you name the two things, blows and caresses, who would not choose the caresses, and decline the blows? If you mark the persons, it is charity that beats, iniquity that caresses. See what we are insisting upon; that the deeds of men are only discerned by the root of charity. For many things may be done that have a good appearance, and yet proceed not from the root of charity. For thorns also have flowers: some actions truly seem rough, seem savage; howbeit they are done for discipline at the bidding of charity. Once for all, then, a short precept is given you: Love, and do what you will: whether you hold your peace, through love hold your peace; whether you cry out, through love cry out; whether you correct, through love correct; whether you spare, through love do you spare: let the root of love be within, of this root can nothing spring but what is good.
9. “In this is love— in this was manifested the love of God toward us, because that God sent his only-begotten Son into this world, that we may live through Him.— In this is love, not that we loved God, but that He loved us:” we did not love Him first: for to this end loved He us, that we may love Him: And sent His Son to be the Atoner for our sins: “litatorem,” i.e. one that sacrifices. He sacrificed for our sins. Where did He find the sacrifice? Where did He find the victim which he would offer pure? Other He found none; His own self He offered. “Beloved, if God so loved us we ought also to love one another. Peter,” says He, “do you love me?” And he said, “I love.” “Feed my sheep.”
10. “No man has seen God at any time:” He is a thing invisible; not with the eye but with the heart must He be sought. But just as if we wished to see the sun, we should purge the eye of the body; wishing to see God, let us purge the eye by which God can be seen. Where is this eye? Hear the Gospel: “Blessed are the pure in heart, for they shall see God.” But let no man imagine God to himself according to the lust of his eyes. For so he makes unto himself either a huge form, or a certain incalculable magnitude which, like the light which he sees with the bodily eyes, he makes extend through all directions; field after field of space he gives it all the bigness he can; or, he represents to himself like as it were an old man of venerable form. None of these things do you imagine. There is something you may imagine, if you would see God; “God is love.” What sort of face has love? What form has it? What stature? What feet? What hands has it? No man can say. And yet it has feet, for these carry men to church: it has hands; for these reach forth to the poor: it has eyes; for thereby we consider the needy: “Blessed is the man,” it is said, “who considers the needy and the poor.” It has ears, of which the Lord says, “He that has ears to hear let him hear.” These are not members distinct by place, but with the understanding he that has charity sees the whole at once. Inhabit, and you shall be inhabited; dwell, and you shall be dwelt in. For how say you, my brethren? Who loves what he does not see? Now why, when charity is praised, do ye lift up your hands, make acclaim, praise? What have I shown you? What I produced, was it a gleam of colors? What I propounded, was it gold and silver? Have I dug out jewels from hid treasures? What of this sort have I shown to your eyes? Is my face changed while I speak? I am in the flesh; I am in the same form in which I came forth to you; you are in the same form in which you came hither: charity is praised, and you shout applause. Certainly ye see nothing. But as it pleases you when you praise, so let it please you that you may keep it in your heart. For mark well what I say brethren; I exhort you all, as God enables me, unto a great treasure. If there were shown you a beautiful little vase, embossed, inlaid with gold, curiously wrought, and it charmed your eyes, and drew towards it the eager desire of your heart, and you were pleased with the hand of the artificer, and the weight of the silver, and the splendor of the metal; would not each one of you say, “O, if I had that vase!” And to no purpose ye would say it, for it would not rest with you to have it. Or if one should wish to have it, he might think of stealing it from another's house. Charity is praised to you; if it please you, have it, possess it: no need that you should rob any man, no need that you should think of buying it; it is to be had freely, without cost. Take it, clasp it; there is nothing sweeter. If such it be when it is but spoken of, what must it be when one has it?
Source: Homilies on the First Epistle of John (New Advent)